Abba Shaul was a Tanna of the third and fourth generations, a contemporary of Rabbi Akiva, whose opinions and disputes he reports; "Abba" is a title and not part of his name. Many of the traditions transmitted in his name concern the Temple and its service, of which he preserved many details, and he compiled a collection of mishnayot from which Rabbi Yehuda HaNasi drew certain passages for the Mishnah.

He is the source of the famous teaching on imitating God: "Be like Him: just as He is gracious and compassionate, so you be gracious and compassionate." He was exacting in matters of holiness: he demanded that levirate marriage be performed solely for the sake of the mitzvah, and added to the list of those with no share in the World to Come one who pronounces the Divine Name as it is written.

He was very tall, so that, according to the Talmud, Rabbi Tarfon reached only to his shoulder. He earned his living as a gravedigger, devotedly attending to the burial of the dead, and kneaded bread in the house of the Nasi.

Tradition attributes a tomb to him; the Arizal, however, taught that another tzaddik, whose name he declined to reveal, lies there.